Refrigerators for professional use, e.g. one used in restaurant kitchens, have a plurality of storing chambers for storing various kinds of foods and drinks. In order to provide such a refrigerator the opening of the refrigerator must have a plurality of thermally insulating partitions and doors for the chambers.
A prior art refrigerator, as disclosed in Japanese Utility Model Early Publication No. 60-5785, has a partitioning member which comprises a U-shaped front panel, a U-shaped cover mounted on the front panel to cover the rear end of said front panel, and an insulation material filling the space formed in said front panel.
The prior art partitioning member as described in the specification and shown in FIG. 2 in Japanese Utility Model Early Publication No. 60-5785, however, has several disadvantages. Firstly, the partitioning member of the refrigerator must be assembled from many components in many steps. Namely, it consists of the front panel, an insulation material, and the cover, with said insulation material being expanded after it is filled in between the front panel and the cover, and the partitioning member is secured at the opening of the refrigerator with screws.
Secondly, in assembling the partitioning member it is not easy to intimately combine the thermal insulator of the partitioning member with the thermal insulator in the wall of the refrigerator, so that their thermal insulation may not be homogeneous from place to place in the refrigerator, thereby resulting in regional water condensation.
Further, when a portion of the refrigerator is used as a freezer, condensed water if deposited on the partitioning member abutting the door freezes, making it difficult to open the door.
Still further, since the wall of the partitioning member and the thermal insulator are in loose contact, the strength of the partitioning member, and hence that of the opening of the refrigerator, is often insufficient. Consequently, it is necessarily to use a thick or strong material to strengthen the walls of the partitioning member.
In most cases such a conventional thermal insulation box is made by filling a thermal insulation material in the hollow space formed in between an inner and an outer box, the outer box usually made of stainless steel plates, and the inner boxes made of thin steel plates, as shown in FIG. 20.
Referring to FIG. 20, a prior art technique for making such inner box of thin steel plate is explained. An inner box comprises three parts, i.e. ceiling panels 90a, 90b, a left and right side panels 91 and 92, respectively, rear panels 93a and 93b, and a bottom panel 94, forming five sides of the box. Since refrigerators for domestic use are smaller in height and width than commercial steel plates, partitioning members may be made without difficulty with these commercially available METAL sheets. However, since refrigerators for business use, such as shown in FIG. 3, have inner boxes larger than the commercially available sheets, use must be made of several sheets for back panels 93a and 93b as shown in FIG. 20.
These plates are secured with screws or stitched together, as shown in FIG. 20. They may be alternatively caulked together as shown in Japanese Utility Model Early Publication No. 44-5415, which teaches caulking of back panels and side panels of the inner box. In any case, use of such panels is not only costly but also requires many assembling steps. Furthermore, since it is difficult to clean the rectangular corners of such inner box, it is preferable to make the corners round. However, fabricating round corners of such panels requires further costly processes.
Japanese Utility Model Early Publication No. 44-5415 teaches injection of urethane as an expandable thermal insulator into a suitable portion of the space between an inner and an outer boxes. In this prior art, although the urethane diffuses to most of the hollow space along the side panels and the rear panel, it might not completely fill up the space behind protruding flange portions connecting adjacent plates, since the flow of urethane is blocked by the protruding flanges.